Emotions that Simmer
by cloudosaurus
Summary: Kacchan chokes Deku, checks him out, and then spoons him. Deku finds that he doesn't really mind. Not that either of them quite realizes their feelings. [BakuDeku. A scoop of unresolved tension with a dollop of fluff.]


Katsuki exhales slowly and stretches his sore muscles, suppressing a tired yawn as he sinks down onto the UA wilderness camp's makeshift bed. Really, it's no more than a pile of wrinkled bedsheets, but right now, it feels like heaven. After a long day of training and a next-level, quirks-allowed game of capture-the-flag during which - Katsuki being Katsuki - he had gone all out (and then some), the blond is more than ready to pass out. Heck, he would have had no trouble conking out like a dead fish even if he was lying in the middle of the forest on a fucking log.

Which is why, when he sees that his tent-mate is _still_ not here - because one, the campers aren't allowed to sleep until they report to Eraser Head that their partner has returned safely (something Iida had excitedly pointed out about being aimed to develop accountability and camaraderie and other related shit ideas) and because two, his assigned partner is friggin' _Deku_ \- a low growl starts to form deep in his throat. When a shadow that looks like the greenhead's combat boots arrives, pauses, and then shuffles unsurely just outside of the ivory canvas curtain, the growl seems to reverberate through Katsuki's limbs before erupting in an enraged cry from his mouth.

"What the hell are you doing, idiot Deku!?" The exasperated teenager yells, bursts of fire forming at the tips of his fingers. "Stop wasting my fucking time! If you're not coming in, just go ahead and say that to Eraser Head. How long are you planning to make me wait for you!?"

If the bespectacled class rep, who is sharing a tent with Tokoyami next door, shouts something about not lighting a fire inside a small, enclosed space surrounded by flammable cloth, it is definitely lost on the blond's ears, which only hear the angry boil of his own blood, and the irritating squeak of rubber on rubber as Deku presses his shoes together nervously.

Then, seeming to steel his nerves, his childhood not-exactly-friend yanks open the curtain. He stands there for a moment looking like a wilted blade of grass, still in his stupidly lame hero costume, as he blatantly avoids Katsuki's burning glare.

"Ss-sorry, Kacchan," Deku stutters, leg tapping - a nervous tic - and hands wringing together - another nervous tic. As always, it totally rubs Katsuki the wrong way.

"If you're fucking sorry, get the hell in so I can finally get some sleep, idiot!"

At this, Deku squeaks. "Y-yes! Sorry!"

The greenhead practically leaps into the shared tent as he sends a message to their homeroom teacher that he and Kacchan are both safely inside. The freckled boy's face is scrunched into that big-eyed, tight-lipped expression that he makes - has made, ever since the two were old enough to walk and talk and play together - whenever the blonde picks on him, and Katsuki, appeased for now, settles back to watch him with narrowed eyes, a scowl the lingering warning of his displeasure.

He studies every part of Deku - from the way he stands awkwardly, shifting his weight from one leg to the other, to the small scars on the back of his shaking fist, and the slight frame that he has watched become leaner and stronger day by day - wondering just when Deku started to become more than the annoying, helpless little kid who always ran behind his shadow. A flame of frustration licks at the insides of Katsuki's stomach as he turns his heated ruby eyes to bore into the greenhead's big, azure orbs. Deku flinches, but doesn't look away this time. The blond bares his teeth and snarls. He doesn't say anything else though, huffing and turning to his side as he tries to smother the embers of jealousy and other feelings that he can't name in favor of sleep. With a fist, he smashes the switch of the lantern laying on the ground beside him.

But he doesn't sense Deku moving from the entranceway. Sure enough, after a few minutes, Katsuki hears the greenhead fidget. It's a quiet sound, and if it had been anyone else, he would have slept despite it and through it. But this is Deku, and _everything_ Deku does drives Katsuki mad.

Fidget. The hairs on the back of the blond's neck stand up. Fidget, fidget. His hands clench into fists. Fidg -

"Argh! Stop fidgeting, you useless idiot! I'm trying to sleep here, I said!" Katsuki yells much louder than necessary and probably wakes up some (or more likely, most) of his classmates. Not that he cares.

"Eeeek!" Deku fucking _squeals_ as he suddenly finds himself face to face with Kacchan, their noses almost touching, the blond teenager having leapt up out of bed to grab the shorter boy by the throat. His other hand is clenched by his side, sparks flying about his fist like a fire floating in the darkened space. The heat of the flames is warm against the greenhead's thigh. He squirms away from the fire, and inadvertently, deeper into Katsuki's hold. The blond tightens his grip around Deku's neck. He feels the blood rushing through the fragile skin, quickened with alarm; sees the freckled boy's eyes open impossibly wide and and glisten with fear as his body goes rigid against Katsuki's.

"Ka - chan!" Deku whimpers, inhaling painfully between syllables. "Plea-"

"I said," Katsuki growls, low and metallic. "Just. Fucking. Sleep." The blond bites out each word in sharp staccatos, and Deku's timed flinches stir something dark inside him.

His voice is huskier than usual when he leans closer. "Unless you want me to _make_ you." Katsuki breathes the words against the hot shell of Deku's ear almost nonchalantly, but the hand curled around the greenhead's throat tightens, squeezing mercilessly. The blond's smirk snakes wider as he feels Deku's pulse trembling beneath his fingertips. It stutters, just like the useless nerd. Oh, he would be so _easy_ to crush. Katsuki squeezes again, harder, and Deku gasps in pain, writhing against his muscular frame and grasping frantically at his hold.

"Aah! Ka-ah!"

It's probably the fact that Deku doesn't even try to put up a fight (and definitely not the moisture he watches collect at the corners of the greenhead's eyes) that finally spurs Katsuki to pull away with a "Tch!", though not without digging his sharp nails into the thin, delicate skin of Deku's neck. The freckled boy cries out and shivers as Katsuki's nails rake a trail that runs from the base of his jaw down to his collarbone. Droplets of blood slowly ooze out and gleam, dark crimson against pale skin, in the glow of Katsuki's flame.

Then, the blond pulls away and extinguishes his fire, the interior of the boys' tent returning to black. Deku collapses to the ground on his knees, panting. He wipes his eyes and brushes a wary hand over the bruised skin of his neck. Katsuki stomps over to his side of the bed and throws himself down onto the messier-than-before sheets with a loud flomp. A few moments pass before Deku dares to speak.

"Um, Kacchan," he begins, voice uneven and raspy. The greenhead winces as the insides of his throat protest with pain, but Kacchan doesn't respond in any way.

Taking that as a good sign, Deku ventures - "I, actually, um, wanted to ask, if you could please, uh, turn the lantern on again, just for a sec." He swallows. "I wanted to change, but um, you kinda shut it off when you went to lay down before, so um …, " the greenhead stammers, and lets the plaintive words hang in the air.

They hover over Katsuki's ears like flies in mid-summer, and he snarls, irritation taking form into red and gold flames that dance dangerously on his palms. But then those flames die out, and are replaced by the soft yellow light of the lantern's bulb as it illuminates the small space.

Deku breathes a shaky sigh of relief that is abruptly cut short as the frowning teen rolls onto his other side - the side facing Deku - and grumbles. Because of course, the final say always belongs to Katsuki.

"Hurry up!" He snarls, brows furrowed and ruby red eyes narrowed as he glares up at Deku. But there's more bark than bite to Katsuki now, and they both know it (even if the blond would never admit that).

Deku hides the small smile that tugs at the corners of his mouth, partly with the welcome realization that Kacchan seems to have burnt out the more aggressive side of his frustration, and partly because the blond's plump lips are amusingly close to a pout.

"Okay," is all that the freckled boy says as he goes about his business. Except that there's a small problem. When he turns around to change, Deku can practically _feel_ Kacchan's eyes burning holes into his back. Sure enough, when the greenhead sneaks a quick peek, Kacchan is propped up on his elbow, spiky blond hair falling sloppily onto his pillow, as he stares unabashedly at Deku's body.

Deku clears his throat nervously.

"Um, Kacchan, is something wrong?"

"No, why?" Katsuki's heated gaze flits up to meet Deku's. The creases between his eyebrows increase visibly, and Deku feels his stomach tighten.

"Uh, just - could you please stop staring?" Deku flushes, heat rising to his cheeks unbidden.

Katsuki's eyes widen the slightest bit at Deku's words, the tension between them dissolving for a fraction of a second, before they narrow again - this time, into an expression of triumphant glee that Deku knows all too well - and the blond's frown transforms into a shiteating grin.

"Ohh, what, insecure, little nerd?" Katsuki taunts, baring sharp teeth in a predatory smile as he slowly trails his eyes over Deku's body.

Once, twice. Up, down. The ruby orbs leave no part of Deku's body untouched, as if burning his very shape into memory. They travel over his toned legs to the slight curve of his hip; from his firm shoulders to the tips of his arms. For the briefest of moments, Kacchan's smoldering gaze lingers at Deku's crotch and then at his chest before returning to his boyish face.

Katsuki looks straight at Deku, darkened, half-lidded eyes seeming to hold promises of sin and pleasure and pain, and _fuck_. Deku's eyes go wide with realization and his knees feel suddenly weak as the blond keeps him pinned under his searing gaze. Katsuki is wearing nothing but a pair of silky black boxers, and when he smirks a lopsided smirk, trailing a palm down the chiseled plane of his bare chest so fucking _suggestively_, Deku's lips open with a soft, wet pop.

For the second time that night, and for an entirely different reason, it feels like all the air has been sucked out of him.

Deku's blood rushes up to set his face on fire. Cheeks burning, he bites his lip as he peels his eyes away from Kacchan's. Because even though Deku knows that it's all for show, the greenhead is suddenly all too aware of how _tight_ his hero costume is and the way that it clings to him like a second skin, leaving nothing to the imagination.

Katsuki lets out a low chuckle. Deku squeaks and spins on his heel, away from the blond, as if a trance has been broken.

"No!" He tries to shout. But the word leaves his throat as a whimper instead, and really, at that moment, he could trade One For All for invisibility.

Katsuki, of course, continues to watch Deku intently, knowing full well that the freckled boy can sense his gaze. The tips of his ears burn scarlet through his unruly mop of green hair, and his legs shake as he starts to undress.

The shoes come off first. There isn't a place to sit, so Deku bends over, untying the laces with trembling fingers that take much too long to do their job. He feels the shallow breaths that flutter nervously in his throat and the heat that is still on his face, and to his horror, seems to be spreading down his neck and warming his entire body. He feels much hotter than he should on a cool spring night. Deku thinks about Kacchan, and about what Kacchan is thinking of as he watches him. The greenhead gulps, wiping a bead of sweat that has formed at his temple. One shoe down. One more to go.

His left boot comes off quicker than his right boot, and then the socks, but then Deku is tempted to put them on again, because he really, _really_, doesn't want to strip in front of Kacchan. The blond is being strangely quiet, and the greenhead wishes that he'd say something - anything - even if it's at his own expense. He chances a glance over his shoulder, and Kacchan catches his eye.

"Hurry up," he growls, even though his brow hadn't been furrowed before the greenhead turned his head, and there's no real menace in his tone. But Kacchan is combustible, as Deku has learned over the years, and his fuse blows without warning. So the freckled boy hurries up, at least as much as he can.

Katsuki stares at Deku as he fumbles with the zipper holding his vegetation-colored ensemble in place. The greenhead's fingers grab clumsily at the small piece of metal, and Katsuki can't fathom why anyone would ever want a zippable suit. _He_ sure as hell wouldn't.

The zipper is on the right side of Deku's costume, hidden underneath a seam that starts at his wrist, runs up the underside of his arm, and then down to his hip bone. The blond teenager leans forward as the zipper is undone and green fabric parts to reveal milky skin. Deku pulls the tab slowly and Katsuki almost hisses with impatience, but then his gaze stills on the myriad of scars that mar the pale flesh. Of course, he _knows_ about Deku's injuries (and obviously, his useless incapability to control his own fucking quirk), but the sight is still so novel that the blond stays silent, following the patchwork of dark scar tissue up to Deku's shoulder. The gashes wind into and over each other - some large, some small, some healed, some fresh - and Katsuki feels a sudden spark of anger burn somewhere deep within his gut.

With a crackle, his emotions burst to life on his palms.

Deku hears the sound of the flames and jolts, frantically yanking the suit down to his hips. He tugs it off his other arm and peels it to the bottom of his torso, where the slight curve of his waist ends, in less time than it had taken to free his right arm alone.

But Katsuki's irritation only flares as he looks at Deku's back. The greenhead is clearly toned, lean muscles well-defined under smooth, supple skin. Hardly a year ago, Deku had been weak and frail, but that would be impossible to guess now. His frame is still slim though, almost feminine, and everything about it from his timid stance to the slender nape of his neck is making Katsuki's blood boil.

"You look like a fucking girl," he spits, small explosions blasting from his fingertips. The air smells like smoke as Deku's shoulders hunch.

"I don't," he says quietly, hands curling into fists at his sides.

"Huh? What was that!?" The blond snarls. He isn't sure what response he wanted from the nerd, but _that_ was definitely not it.

Katsuki creates another explosion, bigger and louder, but Deku doesn't turn to face him. Instead, he slides the rest of his hero costume down his legs until it pools into a green puddle around his ankles.

"I don't look like a girl," Deku repeats, the back of his body now completely exposed for Kacchan to see.

Deku tries to keep his words even, but Katsuki's ears pick up the slight tremor in his voice. He snorts as he rakes his eyes over the freckled boy's body.

The swell of his ass is too plump, white briefs hugging his cheeks too tightly. His thighs are toned but slim, and the milky skin looks too soft. Too bruisable. His calves are just right - shapely but not bulky. He would look too good in heels.

Katsuki says as much.

"You look like you should be fucking a pole in a gay nightclub."

"I do not!" Deku's cheeks glow bright pink as he whirls around to glare at the blond.

He pouts before he can stop himself - eyebrows scrunching, lower lip jutting out ever so slightly - caught between embarrassment and indignation. Because Kacchan has said some pretty awful things to him over the years, but nothing quite like this. So, Deku doesn't know how to react (or whether to react at all) as the blond meets his glare, ferocious and unapologetic.

It's Kacchan who makes it clear just _how_ Deku should be reacting when he scoffs, rolls his eyes, and then raises a contemptuous eyebrow as he drags his piercing gaze down the greenhead's body, inch by fucking inch.

Deku flinches. _Oh, right_. He's basically naked. Realization dawns on him too late and he crosses his arms across his chest protectively, the pink on his cheeks becoming a deep scarlet flush that blazes to the tips of his ears and neck.

Kacchan has seen him in nothing but underwear (and probably less) in locker rooms and hot springs, and the greenhead has never been one to be self-conscious about his appearance. But right now, Deku feels like he's standing on display for the blond to inspect, and his stomach twists and knots in ways he's never felt before. The freckled boy's entire body tenses, and he can't seem to get enough oxygen even though his chest is rising and falling with quick, short breaths.

Deku swallows thickly. His heartbeat is so loud that he's _sure_ Kacchan can hear it. The blond is all golden skin and sculpted muscles as he lies sprawled across the white sheets, looking so damn comfortable in his body. Deku feels a stab of something, he's not sure what. It's not like he _wants_ to care about what Kacchan thinks. But then Kacchan shifts, placing his arms behind his head with a roll of his shoulders, directing his heated gaze to the taut skin of Deku's stomach and the outline of his abs, and the greenhead sucks in a breath, mind going blank as he stands frozen in place.

Deku resists the urge to squeeze his thighs together as the blond's eyes roam lower, and makes a small, strangled noise in the back of his throat when Kacchan's dark ruby orbs linger for a bit too long at his briefs.

As soon as the sound - a humiliating mixture between a whine and whimper - falls from his lips, the freckled boy's face burns impossibly hotter with shame. He cringes and braces himself for more taunts, but they never come. Instead, Kacchan's eyes widen for the tiniest of moments before he whips his head around as though looking at Deku has just burned him.

"Girly-ass nerd," Kacchan growls, but it's under his breath, and Deku is left wondering if he saw a tinge of pink dusting the blond's cheeks as he switches the lantern off with a slam.

It's only once he hears the rustle of Kacchan's blanket that Deku lets go of a breath he didn't know he had been holding. The greenhead's legs tremble as they give out under him, and he falls to the ground on his knees. His heart is still racing, and Deku feels light-headed as he clutches at his chest. He bends over and tries to steady himself, grateful for the darkness that hides him from Kacchan. Deku doesn't want to know what kind of expression he's making.

When his breaths become more even and at least some of the heat has left his face, the greenhead slowly crawls onto his side of the bed, fumbling in the dark. He reaches beneath (what he thinks is) his pillow for his pajamas, and frowns when his fingers find only the soft cotton of a worn t-shirt. Pants. Where are his pants?

With a quiet sigh, Deku decides that it doesn't matter at this point. The last thing he wants to do is test the minefield that is Kacchan's rage by making any noise or asking him to turn the lantern on again. Besides, the freckled boy still feels unnaturally warm all over, so this is probably better. Yep. He has no reason to - and definitely does _not_ \- feel awkward about wearing just a t-shirt and briefs and sleeping next to Kacchan who's wearing just a pair of boxers.

Thankfully, Deku's body doesn't let his mind think about things like that as the day's exhaustion seems to seep into his bones all at once, and he yawns, eyes closing. Inside the tent, the two boys lie still. Outside, crickets sing and leaves dance in the wind as they gleam silver in the moonlight.

"G'night, Kacchan," Deku whispers.

Katsuki huffs.

* * *

Later that night, Katsuki wakes to the feeling of something warm and soft brushing against his arm. At first, he grunts in his sleep, trying to pull away from the thing intruding on his personal space. But the thing, undeterred, clings to him and snuggles closer, so that the warm and soft is now pressed against the side of his stomach. Warm and soft and a bit _wet_, the blond realizes belatedly, forcing sleep-laden eyes open as the shadow of a scowl begins to cross his face. Katsuki can now feel the thing _breathing_, small puffs of air hot against his bare skin, and even though it doesn't seem particularly dangerous (kind of nice, an unhelpful part of his brain thinks), the more lucid part of him is a tad alarmed.

When his eyes finally open though, the blond has to stop and blink, because he has no idea _who_ he is - much less where - in the pitch black. It takes him a few seconds to find the answers amidst the dense fog of slumber, and then remember that he has a quirk. Rational Katsuki instructs sleep-muddled Katsuki to use his quirk to identify the intrusion.

In the gentle glow of the golden flames that flicker above his palm, the blond sees that the intrusion is a freckled boy with moss-green hair and slightly chapped lips - Deku, Lucid Katsuki reminds him, who he should be angry with and push away and yell at. But Sleepy Katsuki is suddenly fascinated by the pink tongue poking out of the greenhead's plump, parted lips, and the tiny bit of drool that glistens wet at the corner of his mouth. He looks so innocent - cute, almost, a treacherous part of Katsuki's mind offers - that he watches transfixed as the freckled boy's long, dark lashes flutter against his cheeks. He wonders what Deku is dreaming about.

And then, the blond realizes that Deku is wearing _his_ t-shirt. An offense that should be punishable by combustion, surely, but the t-shirt is too big and has slid down his neck and to his shoulder, revealing an expanse of pale skin and a collarbone that certainly shouldn't be piquing his interest, and yet most certainly does.

The greenhead tilts his head. It falls onto Katsuki's bicep, and exposes a long, thin line of red that burns angrily against the pearly skin of his neck. _Oh_. Katsuki's scratch. His mark. His mark on Deku. His Deku. Some part of Katsuki might have been - probably is - alarmed by this progression, but his sleep-addled brain seems to like the thought, and he wraps an arm tightly around the freckled boy's sleeping form, pulling him closer to his chest.

Deku sighs softly and arches back into him. His head nestles into the crook of the blond's neck. The greenhead's hair is fluffy. It smells nice and Katsuki wants to bury his nose in it, but then Deku shifts, and the wispy green strands tickle the sensitive skin beneath Katsuki's jaw. The blond twitches, and his legs brush against Deku's.

The contact - unclothed skin on unclothed skin - feels good, so he tangles them together. Deku's legs are longer and leaner than he would have guessed, but his thighs _are_ soft after all, so Katsuki feels rather smug. The greenhead also really does have a bubble-butt, which Katsuki realizes with a shudder when Deku wiggles ever-so-slightly so that the ample curve of his ass is pressed flush against the blond's crotch. Katsuki's mouth goes dry, and he feels decidedly _not_ smug as he heeds the advice of Rational him, who thinks it wouldn't be the best idea to have that ass cozied up to his dick for too long.

Katsuki adjusts their bodies, sliding a hand underneath the t-shirt and over the smooth plane of Deku's stomach, before curling it securely around his waist. Deku's breath hitches as the blond's fingers ghost over taut skin and gently trace the shape of his muscles, and Katsuki is vaguely aware that he's doing something very _wrong_. Something that he's definitely going to regret later. But this also feels very _nice_, so he cuddles the goddamn greenhead closer and wraps a blanket around their entangled bodies.

Katsuki falls asleep breathing in Deku's scent and feeling the steady rhythm of his heartbeat under his palm.


End file.
